1) Serial change of myocardial uptake ratio of I-125 MIBG was investigated in cardiomyopathic hamsters. Myocardial washout of I-125 MIBG was increased in cardiomyopathic hamsters than the controls 4 hours after injection. The cardiomyopathic hamster is characterized by rapid washout I-125 MIBG within 1 hour after injection. These results provided useful information in assessing the mechanism of sympathetic nerve dysfunction in hypertrophic cardiomyopathy.2) Myocardial uptake ratio of I-125 BMIPP was investigated in cardiomyopathic hamster (Bio14.6) with and without administration of Coenzyme Q10. There was no significant difference in myocardial uptake ratio of I-125 BMIPP between them.3) Histopathological examination of myocardial autoradiogram with Gd-C-14-DTPA in cardiomyopathic hamster (Bio14.6) was performed. As the age was older, the left ventricle became hypertrophied and increased in weight and granulation tissues with capillary proliferation and interstitial fibrosis increased on histological sections. Gd-C-14-DTPA showed much accumulation in the tissue with fibrosis. In particular, Gd-C-14-DTPA revealed higher accumulation in the tissues with much capillary proliferation and inflammatory cell infiltration and less collagen fibers.4) After administration of Gd-DTPA to cardiomyopathic hamster (Bio14.6), MR imaging of the excised hearts was performed. MR images of the hypertrophied left ventricular walls showed homogeneous enhancement at age of 3 months old and became inhomogeneous with mixture of strikingly enhanced and unenhanced areas at age of 6 months old. The left ventricle was less enhanced on MR images at age of 10-12 months old.5) Myocardial H-1 spectroscopy was obtained in cardiomyopathic hamster (Bio14.6). The ratio of taurine to phosphocreatimine was significantly higher in cardiomyopathic hamster than that of normal Syrian hamster. The ratio of carnitine to phosphocreatinine became lower at the stages of cardiac failure.